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Design, Manufacture,
and Application of Chamber
for the Magnetohydrodynamic
Deposition Made of PP
Jeremiasz K. Koper
Abstract Magnetohydrodynamic deposition can allow deposition of layers or
particles that are difficult or impossible to obtain by other methods. This is related to
the presence of additional forces during electrochemical processes. Due to the
complexity of the method, it is necessary to properly design and manufacture
the chamber with all parameters in mind. The paper presents the design process and
the chamber manufacture. It is included a detailed description of the method of 3D
printing using PP filament. A test was performed in the chamber, confirm the
significant effect of magnetic field on the iron corrosion processes. The silver
particles deposited on the surface of the titanium at different magnetic field
parameters showed different morphology. Occurrence of the magnetic field has a
significant effect on the current density during of silver deposition process.
Keywords 3D printinng Polypropylene
MHD Silver nanoparticles Titanium
Magnetohydrodynamic deposition
1 Introduction
Many available coatings and particles deposition techniques such as chemical vapor
deposition (CVD), physical vapor deposition (PVD), and plasma enhanced chemical vapor deposition (PECVD) are existing for use on ceramic and metallic substrates [1]. One of the most commonly used methods is deposition of pure metals on
conducting surface by electrolytic methods [2]. Various techniques are used to
obtain different morphologies and structures of the deposition coating.
An alternative may be the deposition of metals and their particles from the
electrolytes by the magnetohydrodynamic method (MHD). In a time of depositing
by this method, additional ionic force occurs. This force supports the deposition
process according to Lorentz’s generally accepted force [3]. This force acts on the
J.K. Koper (&)
Poznan University of Technology, Poznan, Poland
© Springer International Publishing AG 2018
A. Hamrol et al. (eds.), Advances in Manufacturing, Lecture Notes in Mechanical
J.K. Koper
moving charge by accelerating it in a direction perpendicular to the current and thus
leading to electrolyte mixing. This effect can lead to increased mass transfer during
cathode deposition [4, 5]. Another strength is the strength of the field gradient. This
is the force acting on paramagnetic ions in regions with high-density magnetic flux
and diamagnetic ions in regions with low magnetic flux density [3]. This strength is
insignificant in homogeneous magnetic fields, but its effect can counter Lorentz’s
power when there are high magnetic flux density gradients [6]. Force balancing is
expected to be dependent on the concentration of paramagnetic ions in the
homogeneous magnetic field and directed toward higher concentration gradients
indicating the same direction as the diffusion in the electrolyte [7, 8]. However,
some authors indicate that this force has no measurable effect on electrochemical
processes [3, 9].
The effect of magnetic field on corrosion of metals such as iron is important for
technology. It has been shown that the potential of passivation is lower as for more
noble materials. Magnetic field is applied when its flow is perpendicular to the flow
of current [10]. Explaining this phenomenon is the effect of MHD powered by the
Lorentz Force.
The effect of a constant magnetic field with magnetic induction values ranging
from zero to 1 T was investigated in various configurations with respect to the
electrode surface [11]. It was observed that the homogeneous magnetic field applied
parallel to the surface of the electrodes increased the current density and deposition
rate. The obtained results show that the use of homogeneous magnetic field causes
changes the kinetics of the deposition of alloys, change in chemical composition of
deposited alloys, and their surface morphology as well as changes in crystallographic parameters of alloys [12].
Observations of mass transport measurement were increased by diamagnetic
elements (Ag+, Zn2+, Bi3+) and paramagnetic (Cu2+, Ni2+). Theoretical models of
hydrodynamics of magnetic field influence on electrochemical processes have been
developed [13]. Microscopic images confirmed magnetohydrodynamic flow in the
electrolyte and that it is more intense when the direction of vector (B) is parallel to
the electrode’s working surface than when it is perpendicular to the electrode’s
working surface [14].
Presented research gives hope to change the dynamics of deposition for metals.
It may have a significant impact on the applicability of the produced layers by this
method. However, it is necessary to properly design a chamber that enables the
deposition of metal in the additional magnetic field.
2 Design
Design chamber assumptions:
1. Use of electromagnet JARZMO BH-2 with the VoltCraft PS1440 power
supply; 2. Magnetic field minimum 1 T; 3. Minimum samples size Ø10 mm; 4.
Possibility of placing samples in a perpendicular and parallel position to the
Design, Manufacture, and Application of Chamber …
magnetic field force lines; 5. Chemical resistant for acid and temperature up to
100 °C; 6. Electrolyte mixing; 7. Measurement current density by standard reference electrode through Lugin’s capillar; 8. Volume of chamber minimum 50 ml.
Design constraints:
Ad. 1 and 2—Extend of magnets up to a distance of 20 mm give 1 T magnetic
field in the working space (measurement by halothrometer ASONIK SMS 102).
Ad. 3 and 4—Maximum extended magnets (20 mm) give a possibility of using
4 mm chamber construction wall. Such maximum wall thickness will allow sample
placement perpendicular and parallel position to the magnetic field force lines.
12 mm wide will also allow using a standard reference electrode inside the chamber
without the risk of shielding the part.
Ad. 5—due to the aggressive environment and high temperature, the best
materials will be PTFE, PP, PE.
Ad 6—due to the presence of a strong magnetic field, it is not possible to mix the
electrolyte with a magnetic stirrer. Will be used mechanical stirrer with a blade
diameter of Ø45 mm, ChemL and AG20-S. In order to use such a mixer, the design
of the electrolysis chamber must be brought out of the working area and extended to
the correct dimension.
Ad. 7—designed chamber must be brought out from the opposite side of the
stirrer for the reference electrode. Part of the chamber for the reference electrode
will be in contact with the rest of the cell space only through a Lugin capillary.
Ad. 8—application of extended space for mixer give more space for electrolyte
(<100 ml). Such modification additionally allows easying modify electrolyte in
time of experiments.
Presented project meet all of the presented design assumptions (Fig. 1).
Development of the project in the final version was preceded by the production
many models of the chamber. In order to enable the electrolysis of the available
manufacturing techniques, the 3D model was designed (Fig. 2).
3 Manufacture
Due to lack of access to raw PTFE material in the form of a 60 mm thick board or a
80 mm shaft, start searching another available material meeting the assumed
requirements of chemical resistance.
Another material that meets the requirement is PP. PP is much easier to obtain
but slightly worse chemical resistance and much worse temperature resistance,
however, in an acceptable range of strength. After consultation with the manufacturer’s dealing with the machining of plastic and metal materials, it turned out
that shape of the chamber is difficult to perform.
J.K. Koper
Fig. 1 Chamber project
according to design principles
Fig. 2 3D model designed
This has led to change technology from machining to 3D printing. PTFE due to
its properties and the high melting temperature is not suitable for 3D printing. 3D
printing from PP is also not easy and popular due to the properties of this material
but possible. Only one manufacturer in Europe (Filament PM) produce filament
from specially modified Polypropylene possible to use in 3D printer [15].
The 3D printing was realized using the MakerBot Replicator 2X machine. This
is a machine, which realizes the Fused Deposition Modeling (FDM) process. This
process consists in the layered deposition of heated thermoplastic material in form
of a filament, fed through a nozzle in an extruder directly on a model table.
The polypropylene filament is a difficult material for the FDM technology, due
to its specific mechanical and thermal properties. The main problem during the
presented studies was a selection of proper print parameters for this material, to
obtain stability of the process, enabling its finishing and obtaining a defect-free
product. This was achieved only partially. The following controllable process
Design, Manufacture, and Application of Chamber …
parameters decide about the FDM process stability: temperature of material
extrusion, temperature of modeling table, speed of extrusion, and head movement
and layer thickness.
The parameters above were tested in different ranges. The temperature of 220 °C
was attempted and proper, continuous extrusion was achieved in the nozzle test
mode (launched in the machine control panel by use of the “Load” command,
which activates material feeding and heating process without a table and head
The speed of extrusion and head movement was initially set as a standard for the
ABS material, which is 40 mm/s for the layer contours and 90 mm/s for the internal
filling (infill). This was proven to be not suitable for the PPfilament, because of its
different properties after heating (polypropylene is much more elastic, so it needs
more time to be extruded properly). After a number of experiments by trial & error,
this was reduced to 15 mm/s for both contour and infill. This setting significantly
increases the time of manufacturing, but any speed higher than 20 mm/s results in
holes and other disqualifying material discontinuities present in the final product.
The layer thickness was arbitrarily set to 0.3 mm allows to The MakerBot
Replicator 2X allows obtaining stable 3D prints.
The table temperature was set between 70 and 110 °C. This parameter decides
about sticking the material to the model table. In general, the higher table temperature is recommended for materials with higher processing shrinkage (such as
ABS). The recommended temperature for this filament is between 70 and 90 °C.
Unfortunately, none of the selected values (5 test prints were made, with the step of
10 °C) ensured proper stability of the 3D print. The most acceptable stability was
achieved at 90 °C, so this temperature was selected for the final print (Fig. 3).
The main problems and observations related to the process stability problem
while printing out of the PP filament are:
– mechanical properties during layer finishing—closing the layer contour was not
possible to do. It is performed by a rapid movement of the machine head, to
snap the heated filament; as PP has elongation at break near 500%, so the
remaining filament stuck to the nozzle and later caused visual and shape errors;
Fig. 3 Photos of the chamber made by PP filament printed on a MakrerBocie 3D printer
J.K. Koper
– extrusion defects—typical 3D printing materials, such as ABS or PLA, tend to
extrude in an ordered manner and the extrusion can be easily stopped with no
excess material remaining at the nozzle; the PP tends to form droplets at the end
of the nozzle, these droplets are then left somewhere inside the layer contour;
the layers are uneven and during forming of the next layer, the nozzle collides
with the leftover droplet from the previous layer, causing mechanical defects
inside the part;
– thermal properties—in general, the PP has lower thermal conductivity than the
standard ABS material used in the FDM processes, it also has higher coefficient
of thermal expansion; combined with only partial heating of the working space
(the table is heated, but the ambient temperature during the 3D printing process
is approx. 23 °C), this causes the upper layers of any 3D printed part more prone
to thermal deformations, as the temperature in upper layers is lower than in the
layers closer to the heated table; these deformations cause further shape and
dimensional defects, as well as decrease of process stability.
Finally, after several unsuccessful prints, the part was manufactured repeatedly
two times in a row, with stability and full shape representation achieved (see
Fig. 3). The print took 5 h in total. Unfortunately, there were certain defects,
causing leakage in between spaces of the designed chamber. These defects caused
the authors to try an alternative approach.
The PP chamber was alternatively made by a plastic welding method. For this
purpose, a 2 mm thick polypropylene plate was used. After numerous attempts, the
chamber produced by this method proved to be fully tight and meets the requirements (see Fig. 4). At the end of the production stage, the ready-to-use chamber
was placed in the electromagnetic working area (see Fig. 5). The first tests of the
chamber were then performed.
Fig. 4 Pictures of the
chamber made of 2 mm thick
PP boards by welding
Design, Manufacture, and Application of Chamber …
Fig. 5 Picture of the
chamber in the working space
of electromagnet with
mechanical stirrer mounted
4 Experimental Details
Preliminary attempt to measure the influence of Lorentz force on electrochemical
processes. A 99.7% Titanium sample (0.25 mm foil) was used as a working
electrode, with 99.8% iron (0.1 mm foil) as a counter electrode, and Ag/AgCl
reference electrode. During the test was used electrolyte contains 0.01 M HNO3
Without mixing, constant voltage −1 V, variable magnetic field 1 T (perpendicular
to sample surface).
Studies have been conducted on the basis of previous silver deposition studies
on anodized oxidized titanium [16]. Because of small working space in the chamber
the samples were made of titanium foil (0.25 mm, 99.7%). Sample before use was
sanded on 1500-gage water paper and then polished.
Prior to the silver deposition process, samples were purified with distilled water.
Samples were placed in an electrolyte contains silver and nitrogen ions with concentration 0.01 M with additional mixing. In a time of deposition, set DC voltage
−1 V, according to the OCP, using the low voltage SOLARTRON 1285 potentiostat and Ag/AgCl reference electrode. The deposition process was carried out
under different magnetic conditions.
The use of a counter electrode in the form of a silver plate allowed for the
constant concentration of silver ions. After the process, the samples were dried.
After the deposition process samples were characterized by the SEM and XRD.
5 Results and Discussion
Test with pure iron as a counter electrode without additional electrolyte mixing.
Lorentz’s influence on the behavior of the electrolyte was observed. When the
voltage is applied to the electromagnet (up to 1 T magnetic field), the electrolyte is
automatically mixed by Lorentz’s force, facilitating or hindering the flow of electrical current.
J.K. Koper
In the initial stage, the process went without an additional magnetic field, which
for obvious reasons (corrosion processes) caused a rapid decrease in current density
and the establishment of a relatively constant level. After 60 s and 180 s, the
voltage was applied to the electromagnet which influenced the measurement itself
(strong decrease in the measured current density caused by physical phenomena and
electrical induction on the wires). While the magnetic field was involved, the
corrosion process of the iron electrode was accelerated while the electrolyte itself
swirled, accelerating the ions by repelling them from the electrode. After 60 s of
magnetic field, the voltage of the electromagnets was disconnected, resulting in a
small rise of the measured current density. After complete disconnection of the
magnetic field, the corrosion processes proceeded in a fixed manner at the level
established at the initial stage of the test (Fig. 6).
Test with silver deposition
The nature of the current density curves is the same as for anodized oxidized
titanium surfaces—with the deposition time of the silver particles a slow increase in
deposition velocity is associated with the larger surface area of the conductivity
deposited (silver particles) (Fig. 7).
Fig. 6 Preservation of
electric current density
flowing through an iron
sample during a 1 V
potentiometer test, with a
variable magnetic field with a
negative polarity of 60 s
Fig. 7 Graphs of current
density when depositing silver
particles on titanium surfaces
of samples
Design, Manufacture, and Application of Chamber …
Table 1 Values of the
electrical charge flowed
through the samples during
silver deposition process
Magn. field
Charge Q
0.16 C
0.38 C
0.11 C
Fig. 8 SEM image of sample surface after OCP test (a) after silver deposition (b) silver
deposition in negative magnetic field (c) silver depositionin positive magnetic field (d)
However, the measured values of the electrical charge passing through the
surface are significantly lowered to similar values observed for depositing silver
particles by the positive polarization of the 1 T magnetic field (Table 1). As in
previous studies, it can be stated that when depositing silver in a positive magnetic
field, the electrolyte flowed in a lower electrical charge. The use of negative
magnetic fields has significantly increased the flow of electricity. With such a
substrate, the lowest current was observed during deposition of silver particles
without an additional magnetic field.
The morphology of the titanium specimen after silver deposition without additional magnetic field 1Ag * was characterized by numerous very fine particles of
silver about 100 nm (see Fig. 8b). These distributions were characterized by small
size scattering and a crystalline structure which can be determined by the shape of
J.K. Koper
Fig. 9 XRD spectra of titanium and samples after silver deposition in electrolyte contains 0.01 M
HNO3 and AgNO3 1Ag*, with addition negative magnetic field 2Ag−, and positive magnetic field
the particles. They are spread at regular intervals throughout the sample. In a few
places, there are visible expansions in the form of bands of irregular shape.
The morphology of the titanium specimen after deposition of silver with an
additional magnetic field with negative polarity 2Ag− was characterized by
numerous very fine particles of silver about 100–400 nm (Fig. 8c). These distributions were characterized by small size scattering and a crystalline structure which
can be determined by the shape of the particles. They are spread at regular intervals
throughout the sample. In a few places, there are visible divergences in the form of
irregularly shaped dendrites. The increased current density for this sample was
sufficient for the deposition of deposited silver particles.
The morphology of the titanium sample after silver deposition with an additional
magnetic field of positive polarization 3Ag+ was characterized by numerous very
fine particles of silver about 100–300 nm (Fig. 8d). These distributions were
characterized by small scattering of size and crystalline structure. In a few places,
there are visible divergences in the form of irregularly shaped dendrites.
X-ray deposition of silver specimens was characterized by the presence of
titanium and silver peaks (Fig. 9). No additional peaks or anomalies were found in
any of the samples.
6 Summary
The designed chamber fulfilled its task and allowed for proper deposition of silver
particles on the titanium surface. The 3D printing process was proven to be not fully
suitable for manufacturing this type of part, due to numerous issues with process
Design, Manufacture, and Application of Chamber …
stability and shape defects, causing leakages between spaces of the 3D printed
chamber. However, the 3D printing can be used for preliminary testing and prototyping of such parts, for visual evaluation and initial tests. The studies allowed
obtaining a satisfying combination of process parameters for the polypropylene
material. However, a working, fully functional part had to be made using an
alternative approach of plastic welding.
The designed chamber allowed to observe the influence of the magnetic field on
the corrosive phenomena. During the operation of the magnetic field, increase
electron flow through the electrolyte was measurement. Also electrolyte was
automatically stirring caused by Lorentz force. Both phenomena are not observed
without the action of an additional magnetic field.
The magnetic field affected by the deposition of silver particles on the titanium
surface. Negative magnetic polarization (1 T) caused the acceleration of the
deposition process. On the surface was observed larger particles of silver crystals
compared to silver deposit without an additional magnetic field. Positive magnetic
polarization slowed the deposition process. In this case, the appearance of silver
dendrite was observed with a small amount of crystal deposits.
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